Suspended ceiling construction

ABSTRACT

A suspended ceiling construction comprises a plurality of individual ceiling tiles suspended in rows between evenly spaced, inverted T-shaped support beams comprising vertical support members with flanges extending outwardly from each side of the bottom thereof. Each tile has a kerfed back edge that fits over a flange on a back support beam and an L-shaped front portion having a lower lip that fits under a flange on a front support beam. The side edges of each ceiling tile include longitudinal kerfs therein extending rearwardly from the front portion of the tile, with the kerfs being positioned above the lip on the front portion of the tile by a distance at least equal to the thickness of the flange on the front support beam. Locking splines fit into the kerfs in the sides of abutting ceiling tiles and are slidable from locked positions, wherein the splines engage the flange on the front support beam and hold the front portion of the tiles up against the front support beam, to a released position, wherein the splines are disengaged from the front support beam. At least one of the ceiling tiles is an access tile and comprises open sections above the kerfs on each side of the tile, such that the splines in that tile may fit through these open sections when the splines are in their released positions. These open sections permit the removal of the tiles from the ceiling for access to the space above the suspended ceiling.

United States Patent [191 Moomey SUSPENDED CEILING CONSTRUCTION [75]Inventor: Henry Moomey, Kentwood, Mich.

[73] Assigneez' Harvey J. Geute, Spring Lake,

Mich.

221 Filed: Oct. 19,1973

21 Appl. No.: 407,802

Primary ExaminerErnest R. Purser Assistant Examiner-Carl D. FriedmanAttorney, Agent, or FirmMcGarry & Waters [57] ABSTRACT A suspendedceiling construction comprises a plurality of individual ceiling tilessuspended in rows between [111 3,863,413 51 Feb. 4, 1975 evenly spaced,inverted T-shaped support beams comwardly from the front portion of thetile, with the kerfs.

being positioned above the lip on the front portion of the tile by adistance at least equal to the thickness of the flange on the frontsupport beam. Locking splines fit into the kerfs in the sides ofabutting ceiling tiles and are slidable from locked positions, whereinthe splines engage the flange on the front support beam and hold thefront portion of the tiles up against the front support beam, to areleased position, wherein the splines are disengaged from the frontsupport beam. At least one ofthe ceiling tiles is an access tile andcomprises open sections above the kerfs on each side of the tile, suchthat the splines in that tile may fit through these open sections whenthe splines are in their released positions. These open sections permitthe removal of the tiles from the ceiling for access to the space abovethe suspended ceiling.

6 Claims, 7 Drawing Figures PATENTEUFEBA 4197s SHEET 10F 2 FIGJPATENTEUFEB 41915 3863, 413

SHEET 2 OF 2 FFG.4

SUSPENDED CEILING CONSTRUCTION BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates generally to a suspended ceilingconstruction and more particularly to an improved suspended ceilingconstruction having a concealed support structure and easily removableaccess tiles.

2. Description of the Prior Art Suspended ceilings are well known. Inmost typical suspended ceiling structures, evenly spaced suspensionbeams or support members are suspended from the ceiling or otherstructural members of the enclosure, and individual ceiling tiles ofvarious sizes are suspended between adjacent support members. Thesupport members may be concealed or visible from a position below theceiling structure, with the concealed support structures involving morecomplex structural problems than ceilings with visible supports.

Two of the most common types of suspended ceilings in use today areT-Bar and Z-Bar type structures. In a T-bar grid structure, the supportstructure comprises a rectangular grid or matrix of inverted T-shapedmembers or T-bars suspended from the ceiling. The T-bar structure may bevisible or concealed, depending on the ceiling tiles mounted in thegrid. A visible T-bar system is called a conventional grid" system,while a concealed T-bar system is called a concealed grid" system.

In a conventional grid system, individual ceiling tiles rest on theupper surfaces of the horizontal flanges of the T-bars. In this type ofconstruction, access to the space above the ceilingis provided bylifting the tiles upwardly out of the gridwork.

One problem with this type of system is that the flanges on the T-barsare fully visible from below the ceiling, thus impairing the aestheticqualities of the ceiling and making it necessary to employ finishedmetal in the T-bars so that the visible portions will be as unobtrusiveas possible.

Another problem with a conventional grid system is that the ceilingtiles must be lifted upwardly to gain access to the space above thesuspended ceiling. This upward removal requres extra clearance betweenthe suspended ceiling and any structure or ductwork above the suspendedceiling. Three inches of clearance may be necessary for reasonableaccess. In cases where this extra clearance is not possible or isomitted through poor installation procedures, it is quite difficult togain access to the space above the tiles.

in concealed grid T-bar structures, the tiles have a kerf in the outsideedges thereof and the tiles are fitted over the edges of the horizontalflanges on the T-bars. The grid members are concealed with this type ofsystem, but the tiles are not removable and must be broken to gainaccess to the space above the suspended ceiling.

In a Z-bar type of structure,-the support structure for the suspendedceiling is formed of evenly spaced parallel support members calledZ-bars, which typically are suspended from C-shaped channel members(typically 1 V2 inch channel members) that are spaced evenly across theentire width of a room and run in a perpendicular direction with respectto the Z-bars. The channel members are suspended from the ceiling bysuspension wire, and the Z-bars are suspended from the channel membersby spring wire clips. The Z-bars are similar in cross sectionalconfiguration to the T-bars of a concealed grid structure in that theZ-bars have a vertical support member with horizontal flanges extendingoutwardly from the bottom in an inverted T-shaped, member. However, theZ-bars also have a horizontal flange extending outwardly from the top ofthe vertical support member, thus giving the member a roughly Z- shapedcross section. The flange at the top is designed to engage spring clipsthat hold the Z-bar to the transverse channel members.

The ceiling tiles conventionally employed in a Z-bar structure aretwelve inch square tiles, with each tile having a continuous kerf in theside running around the entire tile. The kerf on the back edge of thetile fits over a flange on a back Z-bar, and the kerf on the front edgeof the tile fits over a flange on a Z-bar in front of the tile, with thefront Z-bar being fitted into position after a row of tiles has beenfitted into engagement with the flange on the back Z-bar. Breathersplines," or thin metal plates, are inserted in the kerfs in side edgesof adjacent tiles, in order to close the slots between the tiles andeliminate air flow through the slots.

One of the principal advantages of Z-bar ceilings is that the supportstructure is completely invisible when the ceiling is installed, andthis is a very desirable feature. Accordingly, this type of ceiling hasbeen installed in a high percentage of suspended ceiling installationsover the past few years.

One of the principal drawbacks with a Z-bar type of ceiling structure isthat, like a concealed grid T-bar ceiling, once the ceiling isinstalled, the tiles are perm anently locked in place, and there is noway to-gain access to the space above the ceiling without breaking anddestroying a number of tiles. Reassembly of the ceiling structure afteraccess has been provided similarly is a difficult task. Since it isimportant in many installations that access be provided to the spaceabove the suspended ceiling (e.g., for repair of maintenance of lights,air conditioning, electric'wiring or other utilities), theinaccessability of Z-bar ceiling structure is a serious deficiency withthis type of system.

In order to overcome the problems of inaccessability of suspendedceilings having a concealed support structure, some attempts have beenmade to design removable access tiles for existing concealed grid T-barand Z-bar systems, and other attempts have been made to develop newtypes of ceilings having access tiles. The problems with the accesstiles for ceilings having concealed grids have been that the accesstiles have been too complex and have employed expensive and complicatedclips for holding the tiles in place. In addition, even with workableaccess tiles, convenient access to the space above the ceiling is stilllimited to the space immediately above each access tile, and other tilesstill have to be broken away to provide an enlarged access area oraccess to areas where special access tiles are not located.

One of the principal problems with other types of ceiling structureshaving access tiles is that they do not employ Z-bar ceiling or T-barsupport structures but employ special ceiling supports designedespecially for that particular ceiling. Hence, in the vast majority ofexisting installations, wherein Z-bar or T-bar support structures arealready in use, it would be necessary to remove and discard the entiresupport structure in order to switch over to a new type of ceiling.Other problems with these other types of ceiling structure's 3 are thatthey frequently are difficult to install and remove.

The present invention obviates the foregoing deficiencies in the priorart and provides a simple and inexpensive suspended ceiling constructionhaving concealed support members and simple downwardly removable accesstiles that may be suspended from either a Z-bar or a T-bar supportstructure.

SUMMARY OF THE INVENTION In accordance with the present invention, asuspended ceiling construction having concealed support members that issimple and easy to construct, yet provides easy access to the spaceabove the ceiling, comprises a plurality of evenly spaced, coplaner,parallel support beams suspended from the ceiling, and a plurality ofremovable ceiling tiles suspended in rows between each pair of spacedfront and back support beams.

Each support beam has back and front support means which support thefront and back edges, respectively, of adjacent rows of ceiling tiles.Preferably, each support beam has an inverted T-shaped cross section andcomprises a vertical support member comprising as back and front supportmeans horizontal flanges extending outwardly from each side of thebottom of the support member. An existing T-bar or Z-bar supportstructure may be utilized in the suspended ceiling construction of thepresent invention.

The ceiling tiles each comprise a back edge having a longitudinal kerftherein that fits over and conceals the forward extending flange on theback support beam and an L-shaped front portion having a lower lip thatfits under and conceals the rearward extending flange on a front supportbeam, with the space over the flange on the front support beam beingopen. The sides of the ceiling tiles comprise longitudinal slots orkerfs therein which preferably are spaced above the lip on the frontportion of the ceiling tile. The distance between the lip and the kerfsshould be at least equal to the thickness 1 of the flange on the frontsupport beam.

The front portions of the tiles are held in place against the flanges onthe front support beams by locking means in the form of flat lockingsplines which fit in the kerfs in the sides of adjacent tiles and areconcealed from view. Each spline is slidable from a locked position,wherein the spline extends over the flange on the front support beam andholds the adjacent tile in place, to a released position, wherein thespline is disengaged from the front support beam, thus releasing thefront portion of the ceiling tiles from the front support beam.

The ceiling construction of the present invention includes at least oneaccess tile, which comprises, in addition to the other features of theother ceiling tiles, open sections above the kerfs on each side of theceiling tile, with the open sections being sufficiently large to permitthe spline engaged in that ceiling tile to pass through the open sectionwhen the spline is placed in its released position. Thus, when thespline is in its released position, the access tile drops downwardlyaway from the splines on each side of it and may easily be removed froma row of ceiling tiles suspended between two support beams, the spaceopened up by the removed access tile makes it an easy job to remove anynumber of the other tiles in the row at the same time. Normally, everyother tile in the suspended ceiling is an access tile, in order tomaximize access to the space above the ceiling.-

Each spline is a flat, plate-shaped element having rounded edges, andeach spline is provided with a tool receiving means that is adapted toengage a flat disengaging tool inserted between adjacent tiles. Thedisengaging tool is used to slide the splines between their locked andreleased positions.

One of the important advantages of the ceiling construction is thatconventional or pre-existing Z-bar or T-bar support systems can be used,yet the ceiling has none of the drawbacks of Z-bar or T-bar systems. Thesupport structures are fully concealed but are easily removable in adownward direction to provide maximum access to the space above theceiling. Because the access tiles are removable downwardly, (in contrastwith the upward access of conventional grid systems) the suspendedceiling of the present invention can be placed immediately adjacent tothe structure or ductwork above the ceiling without impairing theremovability of the tiles or access to the space above the tiles.

Another advantage of the ceiling construction of the present inventionis that the tiles and splines themselves are simple and inexpensive andeasy to form, and the ceiling is easy to assemble and disassemble. Theceiling tiles may be formed of any conventional ceiling tile material,and the various cuts and removed sections of the tiles are easily formedby conventional manufacturing methods. Likewise, the splines are simpleflat metal plates having openings in the center thereof for tool access.No interlocking metal parts having rivets and grooves or other suchexpensive and complicated parts are necessary in order to lock theceiling tile of the present invention in position against the supportbeams.

These and other advantages and features of the pres- BRIEF DESCRIPTIONOF THE DRAWINGS FIG. 1 is a broken perspective view of a section of thesuspended ceiling construction of the present invention.

FIG. 2 is a top plan view of a portion of the suspended ceilingconstruction of the present invention.

FIG. 3 is a broken sectional side view of the suspended ceilingconstruction of the present invention, showing the ceiling tilessuspended from a concealed grid support structure.

FIG. 4 is a partial sectional side view of the suspended ceiling of thepresent invention, showing the tiles suspended from a Z-bar supportstructure and showing the junction between the ceiling and a front wall.

FIG. 5 is a partial cross sectional view taken along line 55 of FIG. 4,showing the junction between the ceiling and a side wall.

FIG. 6 is a top plan view of a spline of the present invention.

FIG. 7 is a perspective view of a disengaging tool employed with thesuspended ceiling construction of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring now to thedrawings, a suspended ceiling construction according to the presentinvention comprises a plurality of inverted T-shaped support beams 12suspended from the structure in which the suspended ceiling is beingmounted (e.g., from a fixed ceiling I1), and a plurality of removableceiling tiles 14 suspended between adjacent parallel support beams. Asshown in FIG. 1, ceiling tiles 14 are suspended between adjacent supportbeams in even rows. For purposes of illustration, a single row will bedescribed herein, with the adjacent support beams being identifled as afront support beam 12a and a rear support beam 12b. Similarly,references to forward and rearward directions shall mean toward the leftand right, respectively, according to FIG. 3 orientation. The tiles aremounted edge to edge along the side edges thereof and extend from oneside of the structure to the other as shown in FIG. 5.

Support beams 12 may be any type of inverted T- shaped supportstructure, including the commonly used structure referred to as T-barand Z-bar structures. A T-bar structure 13 is shown in FIGS. 1-3, and aZ-bar support structure 15 is shown in FIGS. 4 and 5.

Each T-bar 13 preferably is formed of a rigid, light weight metal andcomprises a vertical support member 16 having an enlarged rectangularrunner 18 at the top thereof and horizontal front and rear flanges 20aand 20b extending outwardly from each side of the bottom thereof.

Z-bars 15 may be formed of the same type of material as T-bars l3 andalso comprise inverted T-shaped members 16 and 20, as described above.Instead of a runner 18 at the top, however, the Z-bars have an outwardlyextending flange l9. Outwardly extending flange l9 and runners 18 areemployed for the purpose of suspending the support beams from theceiling by different methods, as described below.

Since the inverted T-shaped support beams 13 and 15 operate in the samemanner in suporting the ceiling tiles and differ only in the means bywhich they are supported from the ceiling, these support beamshereinafter will be referred to by the'general reference numeral 12,except where a specific property or function of one of the types ofsupport beams is intended.

T-bars 13 typically are suspended from the ceiling 11 by means of cables22 which are fastened to the ceiling and pass through openings (notshown) in vertical support members 16. Z-bars 15, on the other hand,usually are not suspended directly from the ceiling but are suspendedfrom C-shaped channel members 21 that run transversely to the Z-bars andare evenly spaced across the room or other enclosure in which thesuspended ceiling is mounted. Horseshoe shaped spring clips 23 fit overthe channel members and under the flanges on the Zbars in order to holdthe Z-bars snugly to the undersides of the channel members.

It should be recognized that there are any number of different methodsfor suspending support beams from structural members, and any of thesemethods would be satisfactory means for suspending the support beams ofthe present invention.

Ceiling tiles 14 are rectangular or square in shape and have asubstantially flat back edge 24 (the upper portion is relieved slightlyto accommodate vertical member 16), a stepped or L-shaped front portion26, and opposed side edges 28. Each tile comprises parallel flat top andbottom surfaces and 32, respectively. Typically, in a T-barconstruction, the tiles will be double tiles (FIGS. 1-3), that is, twofeet long and one foot wide, while one foot square tiles (FIGS. 4 and 5)generally are used in Z-bar construction.

The back edge of each ceiling tile 14 is provided with 5 a kerf orgroove 34 between the top and bottom of the ceiling tile. This grooveextends longitudinally the entire width of the tile and tits over frontflange 20a of rear support beam 12b. The back edge 24 of ceiling tile 14thus is supported by support beam 12b and conceals front flange 20a fromview.

The front portion 26 of ceiling tile 14 is L-shaped and comprises alower lip or flange 36 that extends outwardly below rear flange 20!; onfront support beam 120, thus concealing it from view. The ceiling tileis open above flange 2012, so that the ceiling tile requires anadditional retaining member engaging the top of flange 20b to hold thefront of the ceiling tile in place against the from support beam.

The sides of ceiling tile 14 are provided with longitudinal kerfs orgrooves 38 that extend from the front portion of the tile rearwardlytoward the back edge of the tile. Kerfs 38 are positioned in the sidesof the tile above the top of lower lip 36 by a distance at least equalto the width of flange 20b. The kerfs could conceivably be placed atother elevations, but that would eliminate the possibility of using theflat splines, which are described below.

Retaining means for holding the front edges of the ceiling tilesto'flange 20b consists of a plurality of splines or locking members 40which fit within the kerfs in the sides of adjoining ceiling tiles inthe manner shown in FIGS. 1 and 6. Splines 40 are flat, elongated metalmembers having rounded corners. The thickness of the splines is suchthat the splines will fit inside the kerfs 38 in the sides of theceiling tiles. The splines are slidable between a locked position (i.e.,the position shown in FIGS. 1 and 3 and by the solid figure in FIG. 2)and a released position 40' (i.e., the position indicated by the dottedfigures shown in FIG. 2.) In their locked positions, splines 40 extendover flanges 20b and engage the upper'side of flange 20b thus providingsupport for the front portion of the ceiling tiles. In their releasedpositions, splines 40 are disengaged from flange 20b, thus releasing thefront portions of the ceiling tiles from the front support beam.

Splines 40 are provided with tool receiving means 42 in the form ofelongated slots in the center thereof, with slots 42 being formed sothat they will appear between the edges of adjacent tiles. These slotsare adapted to receive a disengaging tool 44 of the type shown in FIG.5.

Disengaging tool 44 comprises a handle 46 and a hooked end 48.1n orderto disengage a tile, disengaging tool 44 is slipped between adjacenttiles in a ceiling section and into slot 42 in a spline. A spline isthenmoved rearwardly to its released position, thus releasing the front edgeof the tile.

With all of the tiles formed in the manner discussed above, movement ofsplines to their released positions will disengage adjacent tiles fromthe front support beam, but the tiles will still be suspended in theceiling structure because of the continued engagement of splines 40 withthe sides of adjacent tiles. In order to permit the complete removal ofcertain ceiling tiles, which will hereinafter be referred to as accesstiles (e.g., tile 14' in the drawings) the kerfs on the sides of theaccess tiles are provided with open sections 50 at a point to the rearof the front of the tile. These open sections are formed such that whenthe splines engaging the kerfs in the'sides of the access tile are movedback to their released positions, the splines not only become disengagedfrom flange 2012 but also become disengaged from the upper surfaceof-kerf 38. In the released position shown by splines 40 in FIG. 2, theceiling tile is not retained in place by either the splines or the frontsupport beam and thus drops easily out of the ceiling structure, withoutaffecting the position or suspension of adjacent tiles.

Since the removal of access tile 14 provides an open space between anotherwise tight row of ceiling tiles, any additional number of ceilingtiles may be removed from this row simply by sliding the other ceilingtiles partially over into the space occupied by the removed access tile,thereby disengaging the splines in the sides of the tile from adjacenttiles. By disengaging the splines, the tiles may be pivoted downwardlyout of the ceiling structure and disengaged from the flange on backsupport beam 12a. In order to avoid the removal of a large number oftiles to provide access to any one particular location, it is preferredthat every other tile be an access tile.

The assembly of the ceiling of the present invention will be describedin connection with the Z-bar embodiments shown in FIGS. 4 and 5. Thefirst step in the assembly involves mounting inwardly facing channelmembers 51 to the walls 53 at the level of the proposed ceiling allaround the perifery of the room. These channel members hold the outeredges of the outer tile in each row. Spring clips 55 may be employed tohold the tiles down in place in the channels. Spring clip 57 at one endof each row resiliently holds the tiles tightly together in the row.

After the channels are installed, a first row of half tiles" (i.e.,tiles that have been cut in half so as to comprise a flat front edge anda kerfed back edge) are fitted into the channels one-by-one with splinesbeing placed between each pair of tiles as each tile is installed. Afterthe entire row has been fitted into the channel, a Z-bar is then fittedinto the back edges of the tiles and clipped up to spaced C-shapedchannel members running in a transverse direction across the room. Thesemembers usually are suspended from the room during original constructionand do not have to be mounted by the ceiling installer.

After the first Z-bar is fitted, a second row of tiles is installedbehind the Z-bar. The outer ends of the-row of tiles are supported inthe side channels and the front edges are suspended from the flange onthe Z-bar by the splines fitted between each pair of tiles in the row.This lets the back edge sag somewhat.

The next step is to fit a second Z-bar into the kerfs in the backs ofthe tiles in the row and then clip the Z-bar up to the channel members.This same procedure is followed until the suspended ceiling covers theentire room.

As the foregoing indicates, the construction of the ceiling of thepresent invention is a relatively simple task. Removal of access tile islikewise a simple task. An access tool is fitted between the edges of anaccess tile and its adjacent tile and the splines are moved back totheir released positions. The access tile then drops down and is slippedoff the back flange and removed from the ceiling.

In order to provide maximum ease of assembly and access to the spaceabove the ceiling tiles, it is desirable that each row of tiles includeat least one access tile.

Preferably, every other tile is an access tile, so as to permit freeaccess to the space above the ceiling structure at any of the number ofpositions.

It should be understood that the embodiments described herein are merelyexemplary of the preferred practices of the present invention and thatvarious changes, modifications, and variations may be made in thearrangements, operations, and details of construction of the elementsdisclosed herein without departing from the spirit and scope of thepresent invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A suspended ceiling construction for a structure comprising:

a plurality of evenly spaced, parallel support beams mounted in thestructure, each support beam comprising front and back ceiling tilesupport means on front and back sides thereof;

' a plurality of removable ceiling tiles supported in rows betweenadjacent front and back support beams, each ceiling tile comprising:

a back edge having kerf means adapted to engage the front support meanson the back support beam so as to hold the back edge in place on theback support beam;

a front portion adjacent the back support means on the front supportbeam, but being disengaged from supporting engagement with said backsupport means; and

opposing side edges that abut the side edges of adjacent tiles in thesame row of ceiling tiles said side edges having longitudinal kerfsformed therein;

locking means slidably mounted in the kerfs in the abutting side edgesof adjacent tiles, each locking means being slidable between a lockedposition, wherein the locking means engage the back support means of thefront support beam and holds the front portions of the adjacent ceilingtiles in place against said front support beam, and a released position,wherein the locking means are disengaged from said back support means,thereby releasing the said front portions from the front support means;and

at least one access tile comprising a ceiling tile having an opensection above the kerf on each side of the tile, said openvsection beingformed so that the locking means in the sides of the access tile willfit 7 through said open sections when the locking means are in theirreleased positions, whereby, access tiles may be removed by sliding thelocking means therein to their released positions and then lowering thetile away from the locking means and disengaging the back edge of thetile from the back support beam. 2. A suspended ceiling construction asclaimed in claim 1 wherein:

each support beam comprises a vertical support member with horizontalflanges extending outwardly from front and back sides thereof, saidhorizontal flanges constituting the front and back support means;

the front portion of each ceiling tile is L-shaped, with a lip on thefront portion fitting under the back flange of the front support beam,the space above the back flange being open; and

the locking means each comprise a locking spline that fits over andengages the top of said back flange when the spline is in its lockedposition.

3. A suspended ceiling as claimed in claim 2 wherein:

the kerfs in the sides of each ceiling tile are formed at a positionabove the lip on the front portion of said tile, with the distancebetween the kerfs and the lip being at least equal to the thickness ofthe back flange on the front support beam; and

the splines are flat, elongated members that are enclosed within thekerfs in the sides of adjacent ceiling tiles, said splines having toolreceiving means therein that are adapted to receive a disengaging toolinserted between the sides of said adjacent tile.

4. A suspended ceiling construction for a structure comprising:

a plurality of evenly spaced, coplaner parallel support beams suspendedfrom the structure, each support beam having an inverted T-shaped crosssection and comprising a vertical support member having front and backhorizontal flanges extending outwardly from each side of the bottom ofthe support member;

plurality of removable ceiling tilessupported in rows between adjacentfront and back support beams, each tile comprising:

a back edge having a longitudinal kerf therein that fits over the frontflange on a back support beam;

an L-shaped front portion that extends to the back flange on the frontsupport beam, with a lower lip thereon fitting under said back flangeand concealing it from view from a position below the suspended ceiling;and

parallel side edges abutting the side edges of adjacent tiles in thesame row and extending between the first and second support beams, saidside edges having longitudinal kerfs therein, said kerfs beingpositioned above the lip on the front portion of the tile by a distanceat least equal to the thickness of the flange on the front support beam;

at least one ceiling tile being an access tile and comprising an opensection above the kerf on each side edge thereof, said open sectionbeing spaced rearward of the front edge of the ceiling tile;

flat locking splines slidably mounted in the kerfs in the side edges ofadjacent ceiling tiles, each said locking spline being slidable from alocked position, wherein the spline extends over the flange on the frontsupport beam and holds the front portion of said adjacent tiles againstthe underside of the support beam, to a released position, wherein thespline does not engage the support beam and the front portion of saidadjacent tiles are not held against the front support beam, said splinesbeing formed so that the splines engaging-kerfs in access tiles fitthrough the opensections therein when the splines are in their releasedpositions, thereby a|-, lowing the access tiles to be removed from theceiling for access purposes without disturbing other tiles, each splinefurther comprising a tool receiving means therein, said tool receivingmeans being adapted to engage a tool inserted between the edges ofadjacent tiles so as to permit movement of the spline between its lockedand released positions.

5. A suspended ceiling as claimed in claim 4 wherein the splines areelongated, flat. plate-shaped metal members, and the tool receivingmeans comprise at least one opening in each spline, said opening beingpositioned so as to be over the abutting side edges of the adjacenttiles in which the splines are mounted.

6. A suspended ceiling construction for a structure I comprising:

a plurality of evenly spaced, parallel support beams mounted in thestructure, each support beam comprising front and back horizontalflanges on front and back sides thereof;

a plurality of removable ceiling tiles supported in rows betweenadjacent front and back support beams, each ceiling tile comprising:

a back edge having a horizontal kerf that fits over the front flange onthe back support beam so as to hold the back edge in place on the backsupport beam;

an L-shaped front portion having a lower lip that extends under the backflange on the front support beam but is disengaged from supportingengagement with said back flange; and

opposing side edges that abut the side edges of adjacent tiles in thesame row of ceiling tiles, said side edges having horizontal kerfsformed therein, said kerfs being formed above the lip on the frontportion by a distance at least equal to the thickness of the back flangeon the front support beam; and

locking splines slidably enclosed in the kerfs in the abutting sideedges of adjacent tiles, each locking spline being slidable between alocked position, wherein the locking spline protrudes over and engagesthe back flange of the front support beam and holds thefront portions ofsaid adjacent tiles in place against said from support beam, and areleased position, wherein the locking spline is disengaged from saidback flange, thereby releasing the said front portions from the frontsupport means, each said locking spline being an elongated, flat memberhaving at least one opening therein, said opening being positioned overthe abutting side edges of the adjacent tiles in which the splines aremounted, and being of sufficient size to receive a disengaging toolinserted between the sides of the adjacent tiles.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION at 3.863.413 DatedFebruary 4, 1974 Inv nt fl HENRY MOOMEY It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In the heading of the patent the assignee's name is "Harvey J. Geute"and should be Harvey J. Beute Signed and sealed this 22nd day of April1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officerand Trademarks 1 FORM (w'ss) USCOMM-DC 60876-P6D ".5. GOVERNMENTPRINTING FF|CB 1 I", 0-366-33l,

1. A suspended ceiling construction for a structure comprising: aplurality of evenly spaced, parallel support beams mounted in thestructure, each support beam comprising front and back ceiling tilesupport means on front and back sides thereof; a plurality of removableceiling tiles supported in rows between adjacent front and back supportbeams, each ceiling tile comprising: a back edge having kerf meansadapted to engage the front support means on the back support beam so asto hold the back edge in place on the back support beam; a front portionadjacent the back support means on the front support beam, but beingdisengaged from supporting engagement with said back support means; andopposing side edges that abut the side edges of adjacent tiles in thesame row of ceiling tiles said side edges having longitudinal kerfsformed therein; locking means slidably mounted in the kerfs in theabutting side edges of adjacent tiles, each locking means being slidablebetween a locked position, wherein the locking means engage the backsupport means of the front support beam and holds the front portions ofthe adjacent ceiling tiles in place against said front support beam, anda released position, wherein the locking means are disengaged from saidback support means, thereby releasing the said front portions from thefront support means; and at least one access tile comprising a ceilingtile having an open section above the kerf on each side of the tile,said open section being formed so that the locking means in the sides ofthe access tile will fit through said open sections when the lockingmeans are in their released positions, whereby, access tiles may beremoved by sliding the locking means therein to their released positionsand then lowering the tile away from the locking means and disengagingthe back edge of the tile from the back support beam.
 2. A suspendedceiling construction as claimed in claim 1 wherein: each support beamcomprises a vertical support member with horizontal flanges extendingoutwardly from front and back sides thereof, said horizontal flangesconstituting the front and back support means; the front portion of eachceiling tile is L-shaped, with a lip on the front portion fitting underthe back flange of the front support beam, the space above the backflange being open; and the locking means each comprise a locking splinethat fits over and engages the top of said back flange when the splineis in its locked position.
 3. A suspended ceiling as claimed in claim 2wherein: the kerfs in the sides of each ceiling tile are formed at aposition above the lip on the front portion of said tile, with thedistance between the kerfs and the lip being at least equal to thethickness of the back flange on the front support beam; and the splinesare flat, elongated members that are enclosed within the kerfs in thesides of adjacent ceiling tiles, said splines having tool receivingmeans therein that are adapted to receive a disengaging tool insertedbetween the sides of said adjacent tile.
 4. A suspended ceilingconstruction for a structure comprising: a plurality of evenly spaced,coplaner parallel support beams suspended from the structure, eachsupport beam having an inverted T-shaped cross section and comprising avertical support member having front and back horizontal flangesextending outwardly from each side of the bottom of the support member;a plurality of removable ceiling tiles supported in rows betweenadjacent front and back support beams, each tile comprising: a back edgehaving a longitudinal kerf therein that fits over the front flange on aback support beam; an L-shaped front portion that extends to the backflange on the front support beam, with a lower lip thereon fitting undersaid back flange and concealing it from view from a position below thesuspended ceiling; and parallel side edges abutting the side edges ofadjacent tiles in the same row and extending between the first andsecond support beams, said side edges having longitudinal kerfs therein,said kerfs being positioned above the lip on the front portion of thetile by a distance at least equal to the thickness of the flange on thefront support beam; at least one ceiling tile being an access tile andcomprising an open section above the kerf on each side edge thereof,said open section being spaced rearward of the front edge of the ceilingtile; flat locking splines slidably mounted in the kerfs in the sideedges of adjacent ceiling tiles, each said locking spline being slidablefrom a locked position, wherein the spline extends over the flange onthe front support beam and holds the front portion of said adjacenttiles against the underside of the support beam, to a released position,wherein the spline does not engage the support beam and the frontportion of said adjacent tiles are not held against the front supportbeam, said splines being formed so that the splines engaging kerfs inaccess tiles fit through the open sections therein when the splines arein their released positions, thereby Allowing the access tiles to beremoved from the ceiling for access purposes without disturbing othertiles, each spline further comprising a tool receiving means therein,said tool receiving means being adapted to engage a tool insertedbetween the edges of adjacent tiles so as to permit movement of thespline between its locked and released positions.
 5. A suspended ceilingas claimed in claim 4 wherein the splines are elongated, flat,plate-shaped metal members, and the tool receiving means comprise atleast one opening in each spline, said opening being positioned so as tobe over the abutting side edges of the adjacent tiles in which thesplines are mounted.
 6. A suspended ceiling construction for a structurecomprising: a plurality of evenly spaced, parallel support beams mountedin the structure, each support beam comprising front and back horizontalflanges on front and back sides thereof; a plurality of removableceiling tiles supported in rows between adjacent front and back supportbeams, each ceiling tile comprising: a back edge having a horizontalkerf that fits over the front flange on the back support beam so as tohold the back edge in place on the back support beam; an L-shaped frontportion having a lower lip that extends under the back flange on thefront support beam but is disengaged from supporting engagement withsaid back flange; and opposing side edges that abut the side edges ofadjacent tiles in the same row of ceiling tiles, said side edges havinghorizontal kerfs formed therein, said kerfs being formed above the lipon the front portion by a distance at least equal to the thickness ofthe back flange on the front support beam; and locking splines slidablyenclosed in the kerfs in the abutting side edges of adjacent tiles, eachlocking spline being slidable between a locked position, wherein thelocking spline protrudes over and engages the back flange of the frontsupport beam and holds the front portions of said adjacent tiles inplace against said front support beam, and a released position, whereinthe locking spline is disengaged from said back flange, therebyreleasing the said front portions from the front support means, eachsaid locking spline being an elongated, flat member having at least oneopening therein, said opening being positioned over the abutting sideedges of the adjacent tiles in which the splines are mounted, and beingof sufficient size to receive a disengaging tool inserted between thesides of the adjacent tiles.